A micro-processor based computer system has the unquestionable ability to manipulate data. Depending on the particulars of software development, manipulation can be internal as well as visually displayed for external control. Visual display is further exploited for interactive user collaboration whereby a means for changing the visual aspects of the display is employed. One such means is cursor control. The most recognized type of cursor control device being the "space bar," a term derived from the extensive use of typewriter-like keyboards for data processing. Data processing with a computer allows the use of advanced cursor control for cursor movement one character left, right, up, or down at a time. As the value of cursor control became evident, computer keyboard manufacturers provided a separate set of arrow keys designated for "manipulation" or "positioning" instead of "control."
Simple cursor control soon became inadequate as a need developed to quickly relocate the cursor with minimum key strokes. The inability to move the cursor quickly, accurately, or diagonally impeded software development. To overcome this limitation, a peripheral device called a "mouse" was created which disregarded the use of keyboard strokes and used a graphics cursor to enhance the methodology of the common cursor. As described in U.S. Pat. No. 4,801,931 by Schmidt, a single trackball is used to turn x and y axis rotational inputs, or both inputs simultaneously. By use of the mouse device, software programs have the flexibility to incorporate graphic cursor functionality into their design. For instance, a mouse allows an operator to "drag" an object across a video screen by first moving the graphic cursor to the object, depressing a mouse switch and dragging the object to any section on the screen. Thus, the conventional cursor was not displaced but enhanced by the graphic cursor allowing complex keyboard operations to be replaced by coordinated cursor positioning with a mouse.
Despite the advantages provided by the graphic cursor, the typical graphic positioner or mouse device remains an external peripheral device. The most efficient means for inputting data into a computer remains the touch typist operator and, despite the use of a mouse for graphic cursor positioning and data manipulation, any time a computer operator is required to remove a hand from the keyboard the operator's efficiency obviously decreases. In addition, the use of a mouse requires additional workspace as well as a special surface for optimum performance.
Portable computer manufactures must address these problems in an effort to retain the true portable nature of their computers. To provide video screen graphic cursor pointing, portable computers require either an external peripheral device, such as a mouse, or extensive keyboard modifications. When using an external peripheral device, the "portability" of a portable computer is considerably degraded. Attachment devices have been developed, or variations thereof eg. joystick, inverted ball, etc. . . , and are currently on the market. U.S. Pat. No. 4,799,049 by Avila and U.S. Pat. No. 4,937,564 by Oberg incorporate rotational and sliding movements into a keyboard embedded device for mouse emulation, yet still require a hand to be removed from the keyboard to operate the graphics cursor positioner. U.S. Pat. No. 4,823,634 by Culver directly addresses the problems associated with removal of the hand from the keyboard by utilizing thumb dexterity for control of a video screen graphic cursor. However, Culver is a keyboard embedded device and as such requires extensive modification to the keyboard. Further, such keyboard embedded devices do not address the optional usage of a co-resident, external video screen graphics cursor pointing device. Such a scheme would allow the user to employ either the keyboard embedded device or an external device, for graphics cursor positioning. Keyboard embedded devices are prone to accidental or inadvertent contact with the operators hand or wrist due to their position on the keyboard and provide no means for preventing the unintended operator contact. Further, the aforementioned devices do not address the inefficient use of the space bar, a carryover from manual typewriters.
The problems described are those which plague the use of graphic cursor control devices. While extensive efforts have been made toward resolving these problems, no satisfactory solution has heretofore been provided. Our invention is specifically designed to overcome the aforementioned problems and further provide a base for future software development needs. It is, therefore, to the effective resolution of these problems that the present invention is directed.